The claim is dramatic: An alternative nuclear fuel that could offer a safer and more abundant alternative to the uranium that powers conventional reactors. That is what supporters have to say about thorium, a mildly radioactive element that occurs naturally, with reserves in Australia, the United States, Turkey, India, Brazil and Venezuela. Scientists promoting thorium as an alternative nuclear fuel believe it is a safer, more economical way of generating nuclear power than uranium. A new report out in the UK, however, begs to differ.